As PCBs increase in complexity it is important to reduce the number of possible errors during the design phase. Completing a sound design will reduce signal integrity issues at a later stage.
An important aspect of PCB board design is signal return current flow, especially for high frequency signals. Signal currents take the path of least resistance which is typically the closest power plane. Therefore, when a signal changes from one layer to another on a PCB, the return current path is interrupted and the return current must also change reference planes, typically via a decoupling capacitor.
In PCB design, improper referencing of signals generates noise, bit errors, reflection and crosstalk. Proper referencing is essential for proper impedance control, loop area minimisation and cross talk reduction. In mixed signal design, proper referencing is essential to prevent analogue and digital signal interference.
A need therefore exists for a method to detect voltage reference errors, for example when a high speed signal is referenced to an improper voltage.